Despite tremendous progress in getting children into the classroom, we are experiencing a global learning crisis, where a large share of children complete primary school lacking even basic reading, writing, and arithmetic skills. What explains this phenomenon? To answer this question, consider the following examples of classrooms that are unlikely to put students on a path to success.

In the first season of The Wire, an American crime drama television series, a young girl who lives in a poor and crime-ridden neighborhood asks Wallace, a teenaged drug dealer, for help with a math problem. It's a word problem that has multiple passengers getting on and off a bus and that asks how many passengers are on the bus at the end of it. The girl is lost. Wallace reframes the problem for her, describing a situation in which different buyers and sellers of crack cocaine take and give her different numbers of vials. When she answers correctly, Wallace asks her why she can't do the same problem when it's in her math book. She explains that if she gets the vial count wrong, the drug dealers will hurt her, so she must get it right.